Well drilling bit



April 15, 1958 E. B. CENTER, JR 2,830,795

WELL DRILLING BIT Filed Nov. 30, 1956 2 Sheets-Sheet 1 "Illl'n INVENTOR. E.B. CENTER,JR.

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A T TOR V5) E. B. CENTER, JR

WELL DRILLING BIT April 15, 1958 2 Sheets-Sheet 2 Filed Nov. 30, 1956 E.B. CENTER,JR.

A 7' TORNEY nited States This invention relates to drilling and means therefor. In a more specific aspect this invention relates to well drilling. In a still more specific aspect this invention relates to the drilling of oil wells by so-called rotary drilling means wherein a drilling fluid is used to carry Well bottom cuttings to the surface, either a liquid drilling fluid commonly called drilling mud or a gaseous fluid, sometimes a relativelyinert combustion or flue gas, or air. And, in a still more specific aspect this invention relates to a new rotary bit structure for use with the usual rotary drilling assembly in drilling oil wells.

Oil well drilling methods and means have long been known in the art, and in particular equipment for the so-called rotary drilling of crude oil or petroleum wells has long been known, including in particular rotary bits which are turned at well bottom by the drill pipe to remove cuttings. These rotary bits are of several kinds, the most popular of which is the cone cutter type bit wherein cone shaped cutters having cutting teeth thereon are rotatably mounted on the bit shank which is turned by the drill pipe in operation. These bits wear out frequently in drilling anoil Well, requiring replacement, or they require sharpening of the teeth, andon each such occasion the entire drill string must be removed from the well, causing a considerable loss of time and being expensive. It is in connection with drilling bits for rotary oil well drilling equipment with which my invention is particularly concerned. The new rotary drilling bit means of my invention has the decided and chief advantage that it will last a long time in one drilling operation, eliminating expensive shut down and repair time, and particularly the time required to remove the drill string from the well, replace or repair the bit, and reinsert the drill'string back into the Well.

The new well drilling tool or bit of my invention has a head portion which is adapted for mounting on a rotary drill string. An elongated hollow member extends from the head portion. This hollow member has a plurality of slots therein which are spaced and which extend spirally of the member. These slots have cutter teeth mounted therein. The cutter teeth extend outwardly and inwardly of the hollow member and they have a lower cutting edge. means upon rotation of the bit in operation to carry cuttings in an upward direction. The teeth are mounted in the slots in the hollow member so as to provide fluid. passageways through the walls of the hollow member for drilling fluid. The head portion of the tool or bit has a conduit therethrough which communicates between the drilling string conduit for drilling fluid and the hollow of the hollow member. The new tool or bit of my invention is adapted when mounted on a drill string and turned therewith in operation to cut material from the well being drilled while receiving drilling fluid and passing same through the passageways in the hollow member to pick up cuttings and carry them to the surface.

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The teeth have upper faces to provide conveyor It isan object of this invention to provide new drilling means.

7 It is another object of this invention to provide new drilling means for the rotary drilling of wells, particularly oil wells wherein a drilling fluid is used to carry cuttings to the surface.

Another object of my invention is to provide a new rotary bit structure for use with the usual rotary drilling assembly in drilling crude oil wells.

Yet another object of this invention is to provide a new particularly rapid, eflicient and easy to operate means for the rotary drilling of oil wells.

Other objects and advantages of my invention will be apparent to those skilled in the art upon reading this disclosure.

Drawings accompany and are a part of this disclosure. These drawings depict preferred specific embodiments of the new drilling tool or bit of my invention, and it is to.

be understood that they are not to unduly limit the scope of my invention.

In the drawing,

Fig. l is a schematic view in elevation of a preferred specific embodiment of the new drilling bit of my invention in operating position in relation to the drill string and related means.

Fig. 2 is an enlarged perspective view of the drill string adapter or shank member of the bit.

Fig. 3 is an enlarged perspective view, partly cut away, of the head portion of the bit.

Fig. 4 is an enlarged side elevation view of a bit tooth mounted in a slot.

Figs. 5, 6 and 7 are enlarged perspective views of the outer, middle and inner tubular members of the bit, re spectively, which carry and mount the cutting teeth of the bit and which are concentrically mounted in the head portion.

Fig. 8 is an enlarged elevation view of a bit tooth.

Fig. 9 is a side elevation view of the tooth.

Fig. 10 is an enlarged partial transverse cross sectional view through the bit showing preferred relative tooth spacing.

Fig. 11 is a perspective view of another preferred specific embodiment of the bit tooth.

Following is a discussion and description of the new drilling means structure of my invention which is made with reference to the drawings whereon the same reference numerals are used to indicate the same parts and/or structure. The discussion and description is of preferred specific embodiments of the new drilling means of my invention, and it is to be understood that such is not to unduly limit the scope of my invention.

In Fig. 1 a preferred specific embodiment of the new drilling bit 14 of my invention is shown mounted in operating position in a well on the lower end of a usual pipe rotary drill string having a string of drill pipe 16 which reaches to the surface. In operation thetelly 18 is turnedby the rotary table means to in turn rotate the drill pipe string 16 to which the Kelly tool is attached. Drilling mud is pumped to the drill pipe via line 20 by pump 22 from mud tank 24. The return mud and cuttings flow around drill pipe 16 within well casing 26, back to the surface and out mud return line 28.

The new drill bit of my invention has a shank 'or adapter member which is threaded in its upper end portion 32 to threadedly engage the lower end of the drill pipe string 16 for mounting bit l lon-the drill string to turn therewith in operation. The lower beveled end 34 of member 36 is suitably attached to the head portion 36 of the bit in its upper beveled end 38 in any suitable manner such as by welding. Adapter or shank 38) is hollow and carries drilling mud from drill pipe 16 to the upper end of head member 36 in drilling operation.

' The head 36 of thebit is in direct communication'with 3. the hollow of adapter 30 to receive drilling mud in operation, and spaced conduits 39 in radially spaced rows and through head 36 deliver drilling mud from adapter 30 to points below the head. In addition, a centraldrilling mud conduit through head 36 is provided by hole 41 therethrough to deliver mud to the cutting points of the bit.

Head 36 is recessed in its lower end portion and has a spaced concentric central groove therein. An outer elongated tubular member 44 is mounted on head 36 around the lower recessed portion to be substantially flush with the outside of the upper portion of head 36, and any suitable mounting means can be used, such as being welded thereto as shown in Fig. 3. A similar middle tubular member 46 is mounted in the circular groove in head 36 and preferably held therein by welding. An innermost tubular member 48 is mounted in the lower end of hole 41, preferably so that the inside of member 48 is substantially flush with the wall of hole 41 in its upper end portion, and member 48 is preferably secured to head 36 by welding.

Each of these concentrically mounted tubular members 44, 46 and 48 have a plurality of spaced slots 50 therein which are preferably elongated as shown. The slots 50 are formed end to end in rows which extend spirally around members 44, 46 and 48 from the lower end thereof to near the head 36 of the bit. There are preferably a plurality of these spaced rows of slots in each tubular member, two in member 48, 4 in member 46 and 6 in member 44 having been found suitable and desirable.

The cutting teeth of the drill are mounted in these slots 50 and preferably welded therein on the lower face of the slots as shown in Fig. 4. The teeth 53 in tubular members 44 and 46 and the one row in member 48 extend inwardly and outwardly of the tubular members. The one row of teeth 55 in tube 48 (Fig. preferably extends only outwardly to a point approximately onehalf the distance between members 48 and 46. By this means the entire area of cutting in drilling the well is contacted by the lower forward cutting edge 57 of the teeth when the bit is rotated. The rows of teeth are preferably offset as between the tubular members as shown in Fig. 10, and this has been found to give desirable results. Teeth 53 and 55 preferably have an outer arcuate edge as shown to fit the well wall contour in operation, and are preferably tiltably mounted as shown in the slots to have an upper face 60 which forms a portion of a flight conveyor, a portion of the spiral flange typical of a flight conveyor. In operation when the bit 14 is turned in the direction of arrow 63 (Fig. 1), the faces of the teeth 53 and 55 act to move cuttings in an upward direction where they are picked up by drilling fluid and carried to the surface. In mounting teeth 53 and 55 in the slots 50 on the lower face thereof, drilling fluid conduits through the walls of the tubular members 44, 46 and 48 are created. In operation drilling fluid from drill pipe 16 passes downwardly through conduits 39 and 41 in bit head 36 and out through slots 50 between the upper faces thereof and faces 60 of teeth 53 and 55. The drilling fluid then picks up cuttings removed from well bottom by the cutting edges 57 of the lower circumferentially spaced row of teeth and moved upwardly by the flight conveyor action of the spirally spaced rows of teeth. These cuttings are carried to the surface by the drilling fluid.

Teeth 53 and 55 are preferably made of a hardened tool steel or similar metal which will last a relatively long time in operation, and as the cutting edges wear, a relatively sharp edge for a slicing type of action is maintained. Tubular members 44, 46 and 48 mounting the teeth are preferably made of a soft metal, considerably softer than that of the teeth so that the tubular material will easily wear away to expose the well bottom to the cutting teeth. In this means one bit 14 will perform a deep well drilling job, for I have found that bit 14 can conveniently be made from 8 to 12 feet long in an approximately 9" outside diameter size, affording many rows of teeth to be used. And, in operation the bit need never be removed from the well, thus saving a great deal of time.

A bit of the structure of my invention can be used in either liquid or gaseous drilling fluid operation. No parts of the bit move in relation to each other and lubrication problems are non existent. Also, the surfaces on the new hit structures of my invention are relatively great affording good contact and conditions for transfer of heat which is built up in drilling due to friction to the drilling fluid. These advantages are particularly of value in gaseous fluid drilling where heat buildup and lubrication of the usual bits are serious problems.

In operation the outer dull arcuate edges of the outer teeth 53 work to firmly shape and maintain the well wall. This is important since there is little or no removal of the drill string from the hole, and caveins, etc., are desirably eliminated. In this connection it is preferred to use the new cutting blade type reamer means of my invention in the drill string along with these new bit means of my invention. The new blade reamer means of my invention is preferably used every few hundred feet in the drill string, and it also acts to help lift drilling mud up the hole to the surface. Such new reamer means of my invention is disclosed and claimed in my co-pending application Serial No. 649,949, filed April 1, 1957.

in Fig. 11 is shown another preferred specific embodiment of cutter tooth for mounting in slots 50 in the manner and position of teeth 53 and 55. Tooth 65 is preferably flat on its upper and lower faces and arcuately shaped on its sides as teeth 53 and 55, and has a similar lower cutting edge 57 which wears away in operation. Tooth 65 has a plurality of spaced transverse slots 67 therein, and as a result of these slots upon wear, a pointed sharp lower edge 57 is always maintained to remove cuttings from well bottom.

As will be evident to those skilled in the art, various modifications of my new drilling means can be made in the light of this disclosure and discussion, without departing from the spirit or scope of the disclosure or from the scope of the claims.

I claim:

1. A well drilling tool, comprising, in combination, a hollow shank member being threaded in its upper end portion for threaded mounting on the lower end of a rotary drill string for turning therewith, a head member rigidly attached to the lower end portion of said shank member to turn therewith, said head member having a recessed lower end portion, a concentric groove in said recessed portion and a central concentric hole therethrough, and spaced conduits in radially spaced rows communicating between the hollow of said shank member and points below said recessed portion, a plurality of such conduits in the spaces between said annular groove and said hole and the outside of said recessed portion, said groove having an elongated tubular member rigidly mounted therein to turn therewith, one mounted around said recessed portion to be substantially flush with the upper portions of said head, and one mounted in said hole, each of said tubular members having a plurality of spaced rows of spaced elongated slots placed end to end, said rows of slots extending spirally around said members from the lower end thereof to a point near said head member and each of said slots having a cutter tooth mounted therein to provide spaced rows of cutter teeth circumferentially and longitudinally, the teeth in the outermost one of said tubular members extending outwardly from said member and inwardly therefrom to a point approximately one-half the distance to the adjacent tubular member, the teeth in the innermost one of said tubular members extending outwardly to a point approximately one-half the distance to the adjacent tubular member with the teeth of one row extending inwardly to approximately the center of the tubular member, and the teethin the other of the tubular members extending both inwardly to points approximately one-half the distance to the adjacent tubular members, each of said teeth being attached to the lower face of said slots, extending the length of said slots, having an outer upper face forming a portion of a flight conveyor, an outwardly, arcuate outer edge and being beveled to have a sharp inner bottom cutting edge, said teeth and the upper faces of said slots defining a plurality of openings through said tubular members for the passage of drilling fluid, the material of said tubular members being softer than that of said teeth, and said tool adapted when mounted on said drill string and turned therewith to cut material from well bottom while receiving drilling fluid from the drill pipe and passing same through said hollow shank member and said conduits in said head member, and out said openings in said tubular members through said slots to pick up cuttings and carry them to the surface.

2. A well drilling tool, comprising, in combination, a head member adapted in its upper end portion for mounting on a rotary drill string to turn therewith, a plurality of elongated tubular members concentrically and rigidly mounted in said head member and depending therefrom, each of said tubular members having a plurality of spaced rows of spaced slots therein, said rows of slots extending spirally of said members, and each of said slots having a cutter tooth mounted therein providing circumferentially spaced rows of cutter teeth with said rows spaced longitudinally, the teeth in said slots extending outwardly from each of said tubular members and having a lower cutting edge, and said teeth extending inwardly from each of said tubular members so that the cutting edges of said teeth in said rows upon rotation of said tool cover the entire transverse cutting area of said tool, each of said teeth having an arcuate outer edge and an upper face to provide flight conveyor means upon rotation of said tool, and each of said teeth being mounted to provide drilling fluid passageways through the wall of said tubular members, drilling fluid conduits through said head member communicating between the drill string drilling fluid conduit and the spaces between said tubular members and within the innermost tubular member, the material of said tubular members being softer than that of said teeth, and said tool adapted when mounted on said drill string and turned therewith in operation to cut material from well bottom while receiving drilling fluid and passing same through said passageways in said tubular members to pick up cuttings to carry them to the surface.

3. The tool of claim 2 wherein said teeth have a plurality of spaced slots therein on the back side thereof and substantially parallel to the cutting edges of said teeth, so that as said teeth wear a sharp cutting edge is maintained.

4. A well drilling tool, comprising, in combination, a head portion adapted for mounting on a rotary drill string, an elongated hollow member extending from said head portion, said hollow member having a plurality of spaced slots extending spirally thereof, at least two of said slots having a cutter tooth mounted therein, said teeth extending outwardly and inwardly of said hollow member and having a lower cutting edge, each of said teeth having an upper face constructed to form flight conveyor means for cuttings upon operation of said tool, and each of said teeth mounted in its slot to define with an edge thereof a drilling fluid passageway through the wall of said hollow member, a conduit through said head portion communicating between the drilling string fluid conduit and the hollow of said hollow member, and said tool adapted when mounted on said drill string and turned therewith in operation to cut material from the well being drilled while receiving driling fluid and passing same through said passageways in said hollow member to pick up cuttings to carry them to the surface.

5. A well drilling tool, comprising, in combination, a. head portion adapted for mounting on a rotary drill string, a plurality of hollow members mounted one within the other in spaced relation in said head portion and depending therefrom, each of said hollow members having a plurality of spaced rows of spaced slots therein, said rows extending spirally of said members, cutter teeth mounted in said slots to form longitudinally spaced rows of cutter teeth, said teeth having a lower cutter edge and the cutting edges in said rows upon rotation of said tool covering the entire transverse cutting area of said tool, the teeth in the outer hollow member extending outwardly and having upper faces constructed to form flight conveyor means for cuttings upon operation of said tool, said teeth being mounted in said slots to define with the edges thereof driling fluid passageways through said hollow members, drilling fluid conduits through said head portion to deliver drilling fluid in operation from the conduit of said drill string to the spaces within said hollow members, and said tool adapted when mounted on said drill string and turned therewith in operation to cut material from said well while receiving drilling fluid and passing same through said passageways in said hollow members to pick up cuttings to carry them to the surface.

References Cited in the file of this patent UNITED STATES PATENTS 

